Fire alarm



July 1968 A. L. LUCAS ET AL F I RE ALARM 2 Sheets-Sheet 1 am PM Z J mm T N I L IDS 7 L D NE 1 RU A m w Filed Nov. 16, 1966 United States Patent 3,391,402 FIRE ALARM Arnold L. Lucas, 448 Wrightwood Ave, Chicago, Ill.

60614, and Walter S. Franczek, 3 N. 470 Willow, Elmhurst, Ill. 60126 Continuation-impart of application Ser. No. 501,102,

Oct. 22, 1965. This application Nov. 16, 1966, Ser. No. 601,271

22 Claims. (Cl. 340-227.1)

This application is a coutinuation-in-part of our copending application, Ser. No. 501,102, filed Oct. 22, 1965, now abandoned and entitled, Fire Alarm.

This invention relates to a fire alarm and more particularly to a self-contained fire alarm which ma be mounted either in a vertical position or in a horizontal position.

Prior to this invention, fire alarms were made and sold, but, for the most part, earlier fire alarms of this nature were more elaborate and were difiicult to install. Some of these fire alarms were also dififieult to calibrate, test and service with the simple tools that are available in the average home. Moreover, these alarms often had a low fire rating and could be rendered inoperative by the heat of a fire before giving adequate alarm.

Accordingly, it is an object of the invention to provide an improved fire alarm.

It is a further object of this invention to provide a fire alarm that may be readily installed in either a vertical or horizontal position.

It is a still further object of this invention to provide a fire alarm that may be easily tested, calibrated and serviced, so the fire alarm is at all times in satisfactory working condition.

Another object of the invention is to provide a fire alarm comprising a container including an alarm compartment, a battery compartment, and a thermostat compartment, wherein the alarm compartment and battery compartment are separate from the thermostat compartment.

Another object of the invention is to provide a battery compartment adapted to detachably mount conventional dry cell D type batteries in series.

Still another object of the invention is to provide a bimetallic thermostat operative between a predetermined temperature range from substantially 120 F. to 186 F., and to provide a bimetallic thermostat in certain high temperature areas operative between a predetermined temperature gradient above the normal ambient temperature.

A further object of the invention is to provide simple means for operatively mounting a bimetallic thermostat within the thermostat compartment, and to provide means for adjusting the bimetallic thermostat within a predetermined temperature range, which bimetallic thermostat comprises a bimetallic strip having a terminal electrical contact at one end and a mating metallic strip having another terminal electrical contact at its end.

Another object of the invention is to provide means for supporting the bimetallic strip of the bimetallic thermostat between the ends thereof to maintain the terminal contact of the bimetallic strip in alignment With the terminal contact of the mating metallic strip.

Another object of the invention is to provide a simple series circuit for the annunciator, the batteries, and the bimetallic thermostat, which circuit is normally open and is closed when the bimetallic thermostat reaches a predetermined and presetable temperature.

Still another object of the invention is to provide grilled passages through the walls of the container for the fire alarm contiguous to and overlying the thermo- 3,391,402 Patented July 2, 1&68

stat compartment to permit the circulation of air through the thermostat compartment whether the fire alarm is mounted in a vertical position or a horizontal position.

Another object of the invention is to provide a fire alarm which is adapted to sound an alarm when a higher than normal predetermined temperature is reached, and wherein the fire alarm is complete in itself and does not require any external source of power supplied to perform its function.

Still another object of the invention is to provide a bimetallic thermostat including a heat sensitive contact wherein the contact is adjustable and only makes contact at a predetermined temperature.

Still another object of the invention is to provide an extension unit for use with the fire alarm, which extension unit has the same arrangement for sensing heat as the fire alarm with which it is used, and is particularly adapted for detecting raised temperatures in areas where an alarm would not be readily heard.

Still another object of the invention is to provide simple means in the form of an extension cord, a plug, and a receptacle arrangement for operatively connecting an extension unit to the principal fire alarm.

Still another object of the invention is to provide a fire alarm wherein one or more extension units may be utilized with the principal alarm for sensing and detecting raised temperatures in remote areas.

Still another object of the invention is to provide an improved container for a fire alarm which container is formed from a material such as plastic which expands under raised temperatures to further insulate the batteries and annunciator so that an alarm may be sounded up to substantially the point of destruction of the container for the fire alarm.

Still another object of the invention is to provide a thermostat for a fire alarm, which thermostat includes a bimetallic element that may be easily adjusted in position to calibrate the thermostat.

In accordance with the above objects a fire alarm is provided which comprises a container including an alarm compartment, a battery compartment and a thermostat compartment, wherein the alarm compartment and battery compartment are separated from the thermostat compartment. The annunciator is operatively mounted within the alarm compartment and the battery compartment is adapted to detachably mount conventional dry cell D" type batteries in series.

A bimetallic thermostat, operative within a predetermined temperature range from substantially F. to F., is mounted within the thermostat compartment. It includes an elongated bimetallic strip rigidly held at one end and a cam-shaped member which holds the thermostat against up and down movement. This construction permits the fire alarm to be mounted in either a vertical position or horizontal position.

The cam-shaped member supports the bimetallic strip between its ends and maintains the terminal contact of the bimetallic strip in alignment with the terminal contact of its mating strip in the thermostat.

A simple series circuit is provided for the annunciator, the batteries and the bimetallic thermostat. This circuit is simply adapted for the connection to one or more extension units each of which includes a bimetallic thermostat for detecting raised temperature in areas where an alarm would not be readily heard. By means of a suitable extension cord and plug, or simple wiring, or if desirable a receptacle for the plug, the alarm signal from a remote extension unit is sent to the principal alarm. The fire alarm of this invention may utilize a plurality of extension units within the capacity of its dry cells.

Air passages formed in the container contiguous to the thermostat compartment and along at least one side thereof provides a simple means for circulating air through the thermostat compartment where its temperature is sensed. These passages permit the flow of air through the thermostat compartment in either a vertical position or horizontal position of the fire alarm.

The invention and the above noted and other features thereof, will be understood more fully and completely from the following detailed description when considered with reference to the accompanying drawings, in which:

FIG. 1 is a front view, in elevation, partially broken away, illustrating an annunciator, batteries, adjustable bimetallic thermostat and compartments therefor of an embodiment of this invention;

FIG. 2 is a bottom view, partially broken away, illustrating the container for the fire alarm of FIG. 1 including the air passages in the bottom edge of the container for circulating air through the container contiguous to the thermostat compartment, the wiring from the battery compartment to the compartment for the alarm device, the wiring from the alarm device to the terminal contact of the bimetallic strip, and the wiring from the battery compartment to the contact of the mating metallic strip in the thermostat compartment;

FIG. 3 is an enlarged view taken along line 33 of FIG. 1 and line 33 of FIG. 4, partly in section, and illustrating a camming means for supporting the bimetallic strip between the ends thereof for maintaining the terminal contact of the bimetallic strip in alignment with the terminal contact of its mating strip therefor, and for adjusting the bimetallic thermostat between a predetermined temperature range at which the bimetallic thermostat will make contact only at a predetermined tem perature setting;

FIG. 4 illustrates a bimetallic thermostat extension unit for a fire alarm wherein the extension unit has the same construction for sensing increases in temperature as the fire alarm of FIG. 1;

FIG. 5 is a perspective view illustrating the fire alarm of this invention mounted upon a vertical wall of an enclosure being protected;

FIG. 6 is a front View, in elevation, illustrating another embodiment of an adjustable bimetallic thermostat which may be used with the fire alarm of this invention;

FIG. 7 is a sectional view taken through lines 7-7 in FIGURE 6, illustrating the improved camming means of this embodiment;

FIG. 8 is a diagrammatic sketch showing the manner in which the camming means of FIGURE 7 operates; and

FIG. 9 is an enlarged front view of the metal strip formin a part of the bimetallic thermostat of this invention.

Referring to FIGS. 1 through 3, there will be briefly described a fire alarm 10 utilizing a buzzer or siren 11 as an annunciator, and preferably two conventional dry cells or batteries 12, which are commercially available for flashlights and are known as size D. There is also used a bimetallic strip 13. The siren 11 and the dry cells 12, which are preferably 1 /2 volts each, are operatively connected in series with the bimetallic strip 13. These elements are commercially available and form no part of this invention except for the novel combination for making an improved fire alarm.

The fire alarm 10 preferably comprises a container 14 and a cover 15 therefor. The container 14 is preferably formed from a general purpose type thermosetting plastic. A resin type amylene material which may be of the class consisting of alpha-amylene or l-pentene, such as used by Plastic Engineering Company of Sheboygan, Wisconsin, is a suitable plastic, a preferred commercial form of which is identified as Plenco Phenolics White No. 800. It is to be understood it is within the scope of the invention that other commercially available plastics of this type may be used. It is preferred to use this type of plastic since, under the action of heat as would be found within the range of temperature found in an enclosure that is on fire, this form of plastic tends to expand with the improved container construction of the fire alarm of this invention. After the plastic has expanded, the container provides better insulation for the components of the alarm, particularly the annunciator, and the circuit of which is closed by the thermostat 13. This mechanization increases the fire rating of the fire alarm so that it tends to sound until the container for the annunciator, components, and circuit therefor are substantially destroyed.

The container 14 has integrally molded from the preferred plastic material an alarm compartment 110, a battery compartment 12a and a thermostat compartment 13a formed by the integrally molded dividers 16 and 17 respectively between the compartments 11a, 12a and 1311, as shown in FIG. 1. The closure 15 of the container is similarly molded to complete the compartments 11a, 12a, and 13a, by having integrally molded dividers or partitions 16- and 17 providing the complementarily formed compartments 11a, 12a and 13a of FIG. 2. It is preferred that the container of the fire alarm shall have peripheral walls and the respective top and bottom walls of the container be molded to a thickness of substantially /s".

The container 14 is preferably formed with a peripheral flange 1S five thirty-seconds inch high with the partitions 16 and 17 being similarly formed. The complementarily formed partitions 16 and 17 of the cover 15 are similarly molded, and the peripheral flange 18' or edge of the cover 15 is complementarily formed to the flange 18 so that a substantially tight or press fit is formed for frictionally afiixing a cover 15 to the base of the container 14. It is also within the scope of the invention that complementarily formed latches, if necessary, may be formed on the peripheral flange of the container and the peripheral edge 18 of the closure to provide a snap fit.

The container 14 is preferably provided with grille work 20 preferably formed in four similar sections 20' each having openings 21 formed by the integrally molded strips 22. The cover 15 is contiguous to the thermostat compartment 13a completing the thermostat chamber 13a, and is similarly formed with grille work 20a provided with similarly formed openings 21a formed by similar integrally molded strips 22a, The grille work 20a has similarly formed sections 20a indicated by the dash lines of the broken away portion of the cover 15.

Referring to FIG. 1, FIG. 2 and FIG. 5, the flow of air through the thermostat compartment while the fire alarm is in the vertical position as illustrated in FIG. 5 will be described. The heated currents of air in the enclosure being protected by the fire alarm 10 flows upwardly through the openings 21 of the grille work as indicated by the arrows 23 and outwardly through the openings 21a of the grille 20a of the cover 15 as indicated by the arrows 23'. In doing so they flow across the bimetallic thermostat 13 which senses any rise in temperature of the ambient air Within the enclosure, within a preferred temperature range of F. and F. This is a preferred sensing range of the fire alarm.

The fire alarm 10 of this invention is equally adapted to be mounted in a horizontal position, such as a ceiling of a room enclosure or over a source of ambient heat such as a furnace and the like, to sense any increase in temperature over the ambient temperature of the furnace room.

When mounted in the horizontal position (not shown) ambient temperature at a present temperature of the bimetallic strip 13 within the predetermined temperature range, for example 120 F. through 180 F., is sensed accurately and the alarm device sounded at the preset temperature level.

Referring to FIG. 1 and FIG. 5, the cover 15 for the container is provided with a circular grille shaped opening 24 having segmentally shaped openings 25, substantially similarly arranged horizontally, spaced apart by similarly arranged segmentally shaped strips 26 which are integrally molded with the cover 15. The circular grille shaped opening 24 is mounted opposite the opening 27 of the siren .11, which the siren is suitably mounted and affixed within the alarm compartment 11a. The circular groove shaped opening 24 in the vertical mounting of the fire alarm 10 disburses the sound emitted by the siren or other form of annunciator outwardly through the openings of the grille work. In the horizontal mounting of the fire alarm 10 on a ceiling or other overhead structure contiguous to a furnace or like source of heat, the sound is directed outwardly and downwardly through the circular grille shaped opening 24.

The siren 11 emits a raucous sound of sufficient decibel strength to attract the attention of any person within or contiguous to the enclosure in which the fire alarm 10 is mounted so that it may be readily heard. Also, the sound is of such decibel strength as to awaken any person who may be sound asleep in the enclosure where the fire alarm is mounted, or even at a distance, for example,

within a home or apartment, which may only have one alarm. However, for the greatest protection of an individual or individuals in a home or apartment, it is preferred to have a fire alarm of this type for each bedroom, in every main room of the home and in the hallways.

Referring to FIG. 1, FIG. 2, and FIG. 3, a simple series circuit 28 of the batteries 12, siren 11, and thermostat 13 will be particularly described as well as the mounting and means 29 for an adjustment to preset the temperature of the bimetallic thermostat 13 within a predetermined temperature range. The siren 11 is actuated by the preset temperature over the ambient temperature to give off an alarm.

In order to mount the 1 /2 volt size D batteries 12, in the battery compartment 12a, an elongated U-shaped battery contact 30 of beryllium copper has its divergent ends 30' symmetrically arranged in the symmetrically formed notches 31 at the upper end of the battery compartment 12a. Similarly formed elongated U-shaped contacts 32 provided with divergently extending ends 32 are complementarily formed to symmetrically formed notches 33 integrally molded in the horizontal divider 17 within the battery compartment 12a. The elongated U-shaped contact 30 and the U-shaped contacts 32 are preferably formed of strip beryllium copper and of a sufficient width to make reliable contact with the positive and negative contacts of the batteries 12. For example, the positive contacts 12' of one of the batteries engages the U-shaped contact 30, and the positive terminal 12 of the other battery engages the U-shaped contact 32 when arranged as illustrated in FIG. 1, so that the batteries 12 are in series.

The series circuit 28 includes a lead wire 34 extending through a notch 35 of the partition 16 and soldered at one end, as illustrated, to the divergent end 32 0f the U- shaped contact 32, and connected at the opposite end to a terminal (not shown) of the siren 11. The other terminal (not shown) of the siren is connected in series by a lead wire 34 extending through a notch 35 complementarily formed to the lead wire 34 in the partition 17, and is connected in series to a terminal 36, FIG. 1. The terminal 36 is afiixed to a rear wall 37 of the container 14 and within the thermostat compartment 13a preferably by a self-tapping screw 38 and spring washer 39. The other terminal 32 of the battery compartment is connected by a lead wire 40 soldered at one end to the divergent end 32 of the terminal 32, and the lead wire 40 extends through a notch 35 of the partition 17 between the battery compartment 12a and the thermostat compartment 13a, and is aflixed to a terminal strip 41 by a self- I tapping screw 38'.

The bimetallic strip 13 is of conventional manufacture and in this embodiment is fabricated to operate within the temperature range of F. and 180 F. It is within the scope of the invention to use other forms of bimetallic strip material to actuate within other predetermined temperature ranges within which it is desired for the fire alarm to actuate. Referring to FIG. 1 and FIG. 3, the bimetallic strip 13 is atlixed at the left end by brazing or soldering to an outwardly extending portion 36' of the L-shaped terminal 36, FIG. 1 and FIG. 4. The opposite end of the bimetallic thermostat 13 is provided with a silver contact 42 which is gold plated for operatively engaging a fixed contact 42' similarly formed of silver and gold plated as the contact 42.

Referring to FIG. 1, FIG. 3 and FIG. 4, the means 29 for adjusting the bimetallic strip 13 between the predetermined temperature range of 120 F. and 180 F., preferably comprises a cylindrical cam 44 eccentrically mounted on the rear wall 37, at the thermostat compartment 13a by a self-tapping screw 45 extending through a spring washer 46 and a tubular spacer 47, and is affixed to a complementarily threaded hole 48 eccentrically mounted with respect to the axis of the cylindrical cam 44. The spring washer 46 permits the tension on the cylindrical cam 44 to be adjusted to frictionally retain the bimetallic strip 13 in any of its adjusted positions within the predetermined temperature range of the fire alarm. The cam 44 is provided with flanges 49 and 50, FIG. 3, to retain the bimetallic strip 13 in any lateral movement of the bimetallic strip 13, as well as up and down movement in the vertical mounting of the fire alarm 10; and similarly, to prevent outward movement, and up and down movement of the bimetallic strip 13 when the fire alarm 10 is mounted in a horizontal position.

The self-tapping screw 45 or other securing means and spring washer 46 is mounted in a recessed opening 46' so that the fire alarm may be mounted flush against a vertical wall or horizontal surface such as a ceiling of a room to which the fire alarm is atfixed. The flange 50 is provided with a slot 51 for receiving a screw driver or coin for adjusting the bimetallic strip 13 between the upper and lower limits of the predetermined limits within which the bimetallic thermostat operates. In this instance the temperature range is indicated by the indicia 52 as being between 120 F. and 180 F. The flange and indicia-bearing dial is integrally molded on the rear wall 37 within the thermostat housing 13a.

As illustrated in FIG. 1, the bimetallic thermostat is set to function at substantially F. Upon the air circulating through the thermostat chamber 13a as described above, and when the temperature of the air within the chamber reaches 155 F., the contacts 42 and 42' will touch as the bimetallic strip 13 moves upwardly since the thermostat is biased upwardly, because of the change in temperature. It is to be understood that the bimetallic strip 13, in this instance, may be properly adjusted for a temperature within the range of 120 F. through F. in which the bimetallic strip functions, or any other range which may be predetermined, and the bimetallic strip selected to operate within this range.

A test hole 53 is provided as illustrated in FIG. 2. It is located in one of the sections 20 substantially intermediate the means 29 for adjustment of the bimetallic thermostat and the end of the thermostat. The end of a pencil or the like may be inserted through the test hole to bias the thermostat upwardly, as illustrated in the dotted position 13' which simulates the position taken by the bimetallic thermostat for the preset temperature of 155 F. for sounding the alarm. The fire alarm may be tested in this manner for any of the present temperatures for which the alarm is set to go off.

In order to mount the fire alarm 10 upon a wall or ceiling of an enclosure, the back or rear wall 37 is provided with key hole slots 54 in a horizontal position. As shown in FIG. 1, one of the key hole slots is in the u per corner of the alarm compartment 11a, and the other is in the corner of the thermostat compartment 13a. They are positioned diagonally one with respect to the other. Suitable securing means such as screws and the like may be furnished for firmly securing the fire alarm in its preferred position whereit may sense very readily any increase within the predetermined range over the ambient room temperature for which the fire alarm is set. It is preferred to position the fire alarm of this invention in one or more places in a building or home, preferably following the circulation of the air within a room or stairwell of a home, if more than one story in height, including all preselected positions within a basement and contiguous to a source of heat within a building.

Referring to FIG. 4, there is illustrated a fire alarm extension unit 10a. This extension unit 10a is substantially the same size as the length and cross-sectional area of the thermostat compartment 13a. The extension unit is preferably formed from the same plastic thermosetting material as the regular alarm enclosure, and the flanges about the opening are similarly constructed as described above with respect to the container 14 and the closure 15 of the fire alarm 10.

In FIG. 4, the extension unit 10a is shown open without a cover 15 (partially shown), but formed substantially peripherally as the cover 15 without the circular grille-shaped opening 24 for the siren. However, the cover 15' (partialy shown) for the extension kit is similarly formed with a plurality of similar sections Each section 20a is formed with similar openings 21a and integrally molded strips 22a forming the openings. The thermostat construction, terminals and means for adjusting are similar to those of the fire alarm, and like reference characters denote the same or similar parts. Therefore, it is unnecessary to further describe the elements of the thermostat control or the operation thereof, since it is the same as that described with reference to the fire alarm 10. The closure 15', broken away, as illustrated in FIG. 4, is also similarly formed with respect to the openings 21a of the sections 20a of the grille work, and where in the openings 21a are provided by the integrally molded strips 22a for each of the grille sections.

The terminals 36 and 41 of the fire alarm extension kit 10a may be suitably connected in parallel by lead wires 36a and 41a to the corresponding terminals 36 and 41 of the fire alarm 10. The lead wires 36a and 41a may extend through suitable grommets 55 of the rear wall 37a. It is also within the scope of the invention that the lead wires 36a and 41a, which may be preferably of hell wire or integrally molded bell wire, be connected by a conventional plug to a complementarily formed receptacle arrangement. Such a receptacle arrangement may be mounted preferably contiguous to the thermostat compartment 13a, or it may be connected in other equally suitable positions and the wires extended to the terminals 35 and 41.

Each extension fire alarm unit 10a may be afiixed to a wall or ceiling of an enclosure being protected thereby, by suitable securing means such as screws or other fastening devices. If more than one enclosure of a building or home is being protected, individual additional extension fire alarm units may be used and suitably connected to the principal fire alarm 10 having the annunciator. It is also within the scope of the invention that, if additional extensions are used, a suitable panel device including individual indicator lights may be connected to each circuit of the fire alarm extension kit to identify at the main fire alarm, the location of any rise in ambient temperature which may be caused by fire or other additional sources of heat to actuate the annunciator when the temperature in the enclosure is raised above the maximum ambient temperature and reaches a preset temperature.

The extension fire alarm unit 10a may be tested by a pencil or the like inserted through the test opening 53'; and likewise, the setting of the bimetallic strip 13 may be set as described with reference to the adjustment of the means for adjustment 29 of the bimetallic strip 13 as described particularly with reference to FIG. 1. In FIG. 4, for example, the bimetallic thermostat 13 is set to go off at a temperature of F. The extension fire alarm unit 10a may also be provided with a notch 35 in which a coin or other tool may be inserted for detaching the cover 15'.

The fire alarm 10 of FIG. 1 and FIG. 2 and the fire alarm extension unit 10a of FIG. 4 may be serviced in the same manner by detaching the respective covers 15 and 15'. In the fire alarm 10, the cover 15 may be removed and the batteries 12 may be removed and checked from time to time so the fire alarm will function at all times. Also the batteries 12 may be replaced when necessary. The thermostat 13 of the fire alarm 10 and the extension fire alarm unit 10a can be similarly serviced and tested.

With respect to the fire alarm 10 when the cover 15 is replaced, the respective flanges of the cover are complementarily formed to the dividers or partitions 16 and 17 so as to effectively seal each compartment comprising the alarm compartment, the battery compartment, and thermostat compartment. The respective lead wires extending through the notches 35, 35' and 35" are also effectively sealed thereby. Thus, the batteries and annunciator are protected from any excess temperature which may be in the thermostat compartment which actuates the alarm device, so that a maximum fire rating and/or period of time within which the alarm device may operate until it fails by destruction is obtained. As described above, the thermoplastic material of the container and cover of the fire alarm 10a may expand, further insulating the compartment of the fire alarm and the devices therein, until there is failure by destruction of the fire alarm with the fire alarm reaching a temperature at which the material forming the container and cover therefor will fail.

FIGURES 6-9 illustrate another embodiment of a thermostat which may be used in this invention. This thermostat is similar in construrtion to the thermostat shown in FIGURES 1, 3, and 4, and is intended to be mounted in a similar manner in the thermostat compartment 130. Because of the many similarities between the embodiment illustrated in FIGURES 1, 3, and 4, and the embodiment illustrated in FIGURES 6-9, it is not necessary to describe many of the features of the latter embodiment in detail. Also, like reference characters in the figures illustrating the two embodiments denote the same or similar parts.

In FIGURE 6 an elevational view of the thermostat compartment 13a and adjacent portions of the annunciator compartment and battery compartment are shown. A metal clip 60 is mounted within a recess in the dividing walls 17 between the thermostat compartment 13a and the annunciator and battery compartments. The metal clip 60 includes a U-shaped portion within the compartment 13a. This U-shaped portion is formed by bending the metal strip over on itself to form a groove 62 opening away from the bottom of the thermostat container 13a. This groove is positioned to receive a dividing wall that is formed integrally with the cover 15 (FIGURES 1 and 2), which dividing wall is formed complementarily with the dividing walls 17. The metal clip 60 secures the cover in position on top of the fire alarm by frictional engagement with the divider within the cover.

The U-shaped clips 32 that are mounted within the battery compartment to make electrical contact with the batteries 12 each include a different bent over metal portion 64 and 66. The bent over metal portions 64 and 66 pass through the dividing wall 17 through the grooves 68 and 70 respectively formed therein. The metal strip 64 includes an aperture which is positioned over the plastic cylindrical binding post 72, which is formed integrally with and is located within the compartment 13a.

The lead wire 34, which electrically connects the annunciator 11 to the terminal 12' of the battery 12 in the series circuit 28, passes through the dividing wall 17 through a groove 74 therein. It is connected at one end to the annunciator 11 and includes at the other end a terminal lug 76 which is positioned over the aperture within the metal strip 64 and ove rthe binding post 72. A self-tapping screw 78 is threaded through the binding post 72 to hold the metal strip 64 and the terminal lug 76 thereto forming an electrical connection between the terminal 12 of the battery 12 and one terminal of the annunciator 11.

A second binding post 36 which is also formed integrally of plastic with the container 14 within the compartment 13a serves a dual function as a binding post for the lead wire 34' and as a support for the bimetallic strip 13. The bimetallic strip 13 fits within the slot 78 of the plastic post 39 and is supported on top of the post by the L-shaped metallic portion 36, which extends orthogonally from the strip 13 at its connecting point 36'. As in previous embodiments, the L-shaped s rip 36 is connected to the lead 34 and the post 39 by a self-tapping screw 38 which is threaded in to the post 39 to hold the terminal lug 80 of the lead 34 and the L-shaped portion 36 in place. It should be noted that the bimetallic strip 13 in the embodiment of FIGURE 6, unlike the former embodiment, is not supported by the cylindrical cam 29.

Another plastic post 82, which also serves the dual purpose of being a binding post and a supporting post, is formed integrally with the container 14 at the right hand side of the compartment 13a. The top portion of the post 82 includes a groove adapted to receive a flat metal strip 84 (FIG. 9) having an elliptical aperture 86 positioned near its outer end 88 and a substantially triangular aperture 90 positioned in line with the aperture 86 and the inner end 92. The upper edge of the metallic strip 41 is connected to the inner end 92 of the supporting strip 84 so that the metallic strip 41 is beneath and orthogonal to the strip 84 and extends towards the left hand side of the container with the contact 42' positioned adjacent to and in line with the contact 42 of the bimetallic strip 1.3.

The bent over metallic strip 66 which connects one of the batteries 12 in the series circuit 28, is positioned over the plastic post 82 with an aperture in its outer end overlying the aperture 86 of the metal supporting strip 84. A self-tapping screw 94 is threaded into the plastic post 82 to hold the strip 84 and the strip 66 in place. A second self-threading screw 96 is threaded through the aperture 90 into the post 82 to provide additional support. The apertures 96 and 90 are used to calibrate the thermostat of this invention in a manner to be described hereinafter.

The metal strip 41 is supported against the horizontal edge of the cylindrical cam 29 as is best shown in FIG- URE 7. The cam 29 is mounted to the raised cylindrical boss 98 which boss is integrally formed with the bottom 37 of the container 14 within the compartment 13a. A cylindrical recess 46' is also formed in the bottom 37 of the compartment 13a contiguous with the raised cylindrical boss 98. The cylindrical cam 44 is mounted to the raised cylindrical boss 98 by a self threading screw 45 which is threaded into the cylindrical cam 29 from the recessed section 46 so that the head of the screw 45 does not protrude beyond the surface of the bottom 37 of the container 14. A metallic spring washer 46 is positioned between the screw 45 and the surface of the recess 46 to provide tension between a cylindrical cam 29 and the raised cylindrical boss 98. This tension may be adjusted so that the cylindrical cam 29 may be manually turned by hand and retain its position when released.

A graduated disk (FIGURES 6, 7 and 8) is mounted on the top side of the cylindrical cam 29 and rotates therewith. The edges of the disk 100 are serrated to form a better frictional contact with the finger of a person who may adjust the activating temperature of the fire alarm. The cylindrical cam 44 may be turned to the proper setting by forces applied to the disk 100. The indicia on the top of the disk (FIGURE 6) are intended to be aligned with a pointing marker 102 formed within the flange 18 of the compartment 14 adjacent to the disk 180. This pointer may be aligned with any one of the lines as shown on the disk 100, which lines also point to a numerical indication between and 180. The numerical indications are in terms of degrees Fahrenheit and indicate the minimum temperature which will actuate the annunicator within the fire alarm.

The cylindrical cam 44 is mounted to adjustably position the metallic strip 41 with respect to the bimetallic strip 13. As the cylindrical cam stem 44 is rotated about the pivotal screw 45 that mounts it to the supporting cylinder 98, it exerts a pressure against the metallic strip 41 moving it further away from the bimetallic strip 13 or permitting it to move closer to the bimetallic strip 13. The manner in which this is done is illustrated best in FIGURES 7 and 8.

The metal strip 41 is supported within the post 82 by the fiat supporting strip 84 in such a position as to always be biased against the side of the cylindrical earn 44. The side of the cam 44 and the edge 92 of the supporting strip 84 are both adjustable and a change in the position of either of these results in a change in the position of the contact 42'. The position of the side of the cylindrical cam 44 is changed by turning the disk 100. This is used to change the minimum temperature for actuating the annunciator after the fire alarm unit has been calibarted.

To calibrate the fire alarm unit, the position of the edge 92 is adjusted. To make such an adjustment, the screw 94 is loosened and the screw 96 is taken out. The indicator disk is turned until one of the known temperature markings such as 120 degrees Fahrenheit is indicated by the pointer 102. The unit is then placed within an oven having a measured temperature of 120 degrees. The supporting plate 84 is then moved until the contact 42 just touches the contact 42. The supporting plate 84 moves with respect to the screw 94 since the slot 86 is elliptical and has its major axis parallel to the slot in the supporting post 82. The top of the loosened screw 94 holds the supporting strip 84 in place so that it only moves back and forth within the slot of the supporting post 82 thus making calibration easier.

The triangular aperture 90 is adapted to be used with a special tool during this calibration process. It must have a sharpened point and a radial portion. This may be formed by filing the end of a screwdriver so that one corner of the screwdriver edge protrudes further than the remainder of the edge. The pointed end may then be inserted into the hole from which the screw 96 has been removed. The fiat portion of the screwdriver end may then engage with the side 94 so that the support 84 is moved forward as the screwdriver is rotated in a clockwise direction. This causes the contact 42. to move away from the contact 42. On the other hand the fiat radial portion of the screwdriver edge may be turned to engage the upper side 96 of the aperture 90. In this case, the support 84 is moved inward as the screwdriver is turned in a counterclockwise direction. This moves the contact 42' towards the contact 42.

After the supporting strip 84 has been moved so that the contact 42 just touches the contact 42, thescrew 94 may be tightened to firmly restrain the support 84 from further movement. The unit may then 'be removed from the oven and the screw 96 inserted and tightened. The unit is now calibrated and may be set for any of the temperatures indicated on the dial 100.

While the invention has been described by means of particular embodiments thereof, it will be understood that those skilled in the art may make many changes and modifications without departing from the spirit and scope of the invention, and accordingly, also such changes and modifications which fall within the true spirit and scope of this invention are intended to be covered in the appended claims.

We claim:

1. A fire alarm comprising a container including an alarm compartment, a battery compartment and a thermostat compartment, said alarm compartment and battery compartment being separate from said thermostat compartment, an annunciator operatively mounted within the alarm compartment, said battery compartment adapted to detachably mount conventional batteries in series, a bimetallic thermostat operative between a predetermined temperature range, said bimetallic thermostat including a bimetallic strip having a contact at one end and being operatively afiixed to the container within the thermostat compartment at the other end, said bimetallic thermostat further including a metallic strip having a contact at one end and being afiixed to the container within the thermostat compartment at the other end, the contiguous other ends of said strips including terminal connections, the contact of the bimetallic strip being aligned with the contact of said metal strip, said annunciator, said batteries, and said bimetallic thermostat being operatively connected in a series circuit, said series circuit being normally open and being operatively closed at a predetermined temperature within the predetermined temperature range, a cover for the container including partitions for sealing off the alarm and battery compartments from each other and the thermostat compartment, said cover being provided with an opening overlying the alarm device for disseminating the sound of the annunciator upon actuation, means for the circulation of air through the thermostat compartment and about the thermostat, said means for circulation of air comprising air passages formed on the cover contiguous to and overlying the thermostat compartment with the cover being operatively mounted on the container, said means for the circulation of air comprising additional air passages formed in the container contiguous to the thermostat compartment and along at least one side of the thermostat compartment, and said means for circulation of air permitting air to circulate through the thermostat compartment in the mounted position of the fire alarm within an enclosure being protected, whereby air for actuating the bimetallic thermostat may circulate through the thermostat compartment in either the vertical position or horizontal position of the fire alarm upon being aflixed to a vertical or horizontal wall surface.

2. A fire alarm as set forth in claim 1, comprising an elongated U-shaped contact including divergent ends, a wall of said battery compartment formed with notches complementarily formed to said divergent ends for detachably mounting the elongated U-shaped contacts and resiliently contacting the terminals of the batteries adapted to be operatively mounted side by side within the battery compartment, two shorter similarly formed U-shaped contacts, each short U-shaped contact including divergent ends, a wall opposite the first-mentioned wall of the battery compartment formed with two sets of notches complementarily formed to said divergent ends of the two short U-shaped contacts for detachably mounting the two shont U-shaped contacts and adapted for resiliently contacting the opposite terminal ends of the batteries, said batteries adapted to be connected in series through the elongated U-shaped contact and the two short U-shaped contacts and adapted to be retained in position within the battery compartment when the fire alarm is operatively mounted within an enclosure being protected.

3. A fire alarm as set forth in claim 1, said annunciator being a siren, said siren operatively mounted within the alarm compartment, a lead wire operatively connecting the siren in series to one of the battery terminals in the battery compartment, a lead Wire operatively connecting the siren in series to the terminal connection of the bimetallic thermostat within the thermostat compartment, a notch for receiving the first-mentioned lead wire in an edge of a partition between the alarm compartment and the battery compartment, another notch for receiving the second-mentioned lead wire in an edge of a partition between the alarm comp-artment and :the thermostat compartment, and means for sealing the notches provided by insulating covering of the lead wires extending through the notches.

4. A fire alarm as set forth in claim 1, comprising a lead wire operatively connecting said bimetallic strip connection of the bimetallic thermostat in series to the alarm device, another lead wire operatively connecting in series said metal. strip of the bimetallic thermostat to a U-shaped contact for one of said batteries operatively mounted in the battery compartment, a notch for receiving the firstmentioned lead wire in an edge of a partition between the alarm compartment and the thermostat compartment, another notch for receiving the second-mentioned lead wire in an edge of the aforesaid between the battery compartment and the thermostat compantment, and means for sealing the notches provided by the insulating covering of the lead wires extending through the notches.

5. A fire alarm as set forth in claim 3, wherein the partitions of the closure are complementarily formed to the portions between the battery compartment and the alarm compartment and operatively abut each other so that the battery compartment and the alarm compartment are sealed along the respective edges of the respective partitions of the cover and container, and sealed at the respective notch for the lead wire extending between the battery compartment and the alarm compartment by the insulation of the respective aforesaid lead wire, and said partitions of the closure are complementarily formed to the partitions between the battery compartment and the thermostat compartment and operatively abut each other so that the battery compartment and thermostat compartment are sealed along the respective edges of the respective partitions of the closure and container and sealed at the respective notch for the lead wire extending between the battery compartment and the thermostat compartment by the insulation of the lead wire extending therebetween.

6. A fire alarm as set forth in claim 4, wherein the partitions of the closure are complementarily formed to the partitions between the battery compartment and alarm compartment in common with the thermostat compartment and operatively abut each other so that the battery compartment, alarm compartment and thermostat compartment are sealed along the edge of the common partition therebetween and sealed at the respective notches for the lead wires extending between the battery compartment and alarm compartment and the thermostat compartment by the insulation of the lead wires extending therebetween.

7. A fire alarm as set forth in claim 1, wherein the closure and container are molded from a thermosetting type resin plastic of the class consisting of a-amylenes and l-pentene so that the temperature of a fire occurring within an enclosure in which the fire alarm is operatively positioned when the temperature of the fire is substantially at the melting point of the thermosetting plastic material causes the thermosetting plastic material to expand providing insulation to the components within the alarm device so that the period of the fire rating of the alarm device is increased allowing the alarm device to keep on actuating until destroyed by fire within the enclosure.

8. A fire alarm as set forth in claim 1, further including a support means for supporting the bimetallic strip between the ends thereof, said bimetallic strip being movable about said other end and biased against said support means, said support means comprising spaced annular flanges, a cylindrical cam for operatively engaging the bimetallic thermostat between the ends thereof, means for eccentrically and frictionally mounting the cylindrical cam on the rear wall of the container and within the thermostat compartment, indicia means contiguous to the movable end of the bimetallic thermostat for indicating the predetermined range of temperature through which the bimetallic thermostat acts, and means provided on one of the flanges of the means for supporting the bimetallic strip for adjusting the bimetallic thermostat within the predetermined range of temperature of the indicia means.

9. As an article of manufacture, a fire alarm comprising a container and cover therefor, said container comprising two partitions for dividing the container into a battery compartment, an alarm compartment and a ther mostat compartment, one of said partitions formed intermediate the ends of the other partition for dividing the container into a battery compartment and an alarm compartment on one side of the other partition, and the remainder of the container into a thermostat compartment, and said cover provided with partitions complementarily formed to the first-mentioned partitions for dividing the cover into compartments corresponding to the battery, alarm and thermostat compartments, and the peripheral edges of the container and cover complementarily formed for frictionally affixing the cover to the container.

10. As an article of manufacture, a fire alarm as set forth in claim 9, in which the partitions are formed with notches adapted to receive lead wires of a series electrical circuit operatively extending across the partitions and operatively connecting the batteries, the siren and the bimetallic thermostat in series.

11. As an article of manufacture, a fire alarm as set forth in claim fi, said partition between the battery compartment and the thermostat compartment and within the battery compartment provided with a plurality of sets of spaced recesses complementarily formed and adapted to receive diverging ends of symmetrically formed and elongated U-shaped contacts.

12. As an article of manufacture, a fire alarm as set forth in claim 9, including a wall of the battery compartment opposite to the partition between the battery compartment and the thermostat compartment provided with symmetrically spaced recesses complementarily formed and adapted to receive diverging ends of a symmetrical formed and elongated U-shaped contact.

13. As an article of manufacture, a fire alarm as set forth in claim 9 in which said closure comprises a grilled opening centrally positioned with respect to the alarm compartment, and similarly spaced grilled openings on the face of the closure overlying the thermostat compartment of the container for receiving the bimetallic thermostat for the circulation of air through the thermostat compartment in the operative and mounted positions of the fire alarm with the closure operatively positioned on the container of the fire alarm.

14. As an article of manufacture, a fire alarm as set forth in claim 9 in which said cover is integrally molded from a thermosetting type resin plastic of the class consisting of a-amylene and l-pentene so that a fire resistant and insulating closure for a fire alarm is provided.

15. As an article of manufacture, a fire alarm as set forth in claim 9 in which said container includes similarly spaced grilled openings on an edge of the container and similarly located as similarly spaced grilled openings on the face of said cover, said spaced grilled openings of the container formed in a peripheral wall of the container contiguous to the thermostat compartment of the container for receiving the bimetallic thermostat for the circulation of air through the thermostat compartment in the operative and mounted positions of the fire alarm with the closure operatively positioned on the container of the fire alarm.

16. As an article of manufacture, a container for a fire alarm including a closure as set forth in claim 14, wherein said container is integrally molded from a thermosetting type resin plastic of the class consisting of a-amylene and l-pentene to provide a fire resistant and insulating container and a similar fire-resistant and insulating cover so as to provide a fire-resistant and insulating battery compartment of the fire alarm.

17. As an article of manufacture, a fire alarm as set forth in claim 9 including a bimetallic thermostat having a bimetallic strip attached to said container at one end and having a terminal contact at the other end and a metal strip having a terminal contact at one end and being fastened to said container at the other end, an indicia for indicating the predetermined temperature range through which the bimetallic thermostat operates, said bimetallic strip at its free end providing a pointer for indicating the preset temperature at which the bimetallic thermostat actuates, and means for presetting the bimetallic thermostat operatively positioned intermediate the ends of the bimetallic strip and adapted for biasing the bimetallic thermostat into its operative position in an atmosphere of heated air circulating about the bimetallic thermostat.

18. As an article of manufacture, a fire alarm as set forth in claim 9 comprising a bimetallic thermostat operatively mounted Within the thermostat compartment, a wall of said thermostat compartment provided with a test opening, said test opening operatively positioned contiguous the free end of the bimetallic thermostat, so that an instrument may be inserted through said test opening biasingthe bimetallic thermostat to its closed position from its normal open position, and said bimetallic thermostat operatively connected in a series electrical circuit including an alarm so that upon the normal open contacts of the bimetallic thermostat being closed, the alarm will sound.

19. In combination. a fire alarm and an extension unit for said fire alarm, said extension unit including batteries and a bimetallic thermostat, said bimetallic thermostat including terminal connections operatively connected in an electrical series circuit, said thermostat extension kit including a container for operatively mounting a bimetallic thermostat similar to the bimetallic thermostat of the fire alarm and a closure therefor, openings provided in a bottom Wall of the container and similar openings provided in the closure cover so that air within an enclosure being protected by the thermostat extension kit in its operatively mounted positions will flow across the bimetallic thermostat for activating the bimetallic thermostat, said bimetallic thermostat operative between a predetermined temperature range from substantially F. to F., mean for operatively mounting the bimetallic thermostat within the thermostat compartment and including a terminal connection at one end operatively affixed to the container within the thermostat compartment, a terminal connection for the other end of the bimetallic thermostat operatively afllxcd to the container within the thermostat compartment, the contiguous other end of the bimetallic thermostat and the terminal connection therefor including terminal contacts, means for supporting the bimetallic thermostat between the ends thereof for maintaining the terminal contact of the bimetallic thermostat in alignment with the terminal contact of the terminal connection, said means for supporting the bimetallic thermostat including cam means for adjusting the bimetallic thermostat within its predetermined temperature range, indicia means for denoting the predetermined temperature range, said bimetallic thermostat at its free end contiguous to the indicia means for the predetermined temperature range and operative as a pointer for presetting the bimetallic thermostat at its operative temperature, a test hole porvided in the bottom of the container for the insertion of a probe for closing the contacts of the thermostat for actuating the alarm device of the fire alarm for testing, and said terminal connections of the bimetallic thermostat of the thermostat extension kit adapted to be connected in parallel to the terminal connections of the bimetallic thermostat in the electrical series circuit therefor so that the alarm device Will actuate at the preset temperature of the bimetallic thermostat of the thermostat extension kit, and said openings in the container and the closure providing means for circulating air therethrough in the mounted position of the thermostat extension kit in an enclosure being protected, whereby air for actuating the bimetallic thermostat may circulate through the container for the bimetallic thermostat in either the vertical or horizontal position of the thermostat extension kit, upon being affixed to a vertical or horizontal wall surface.

20. As an article of manufacture, a fire alarm as set forth in claim 9 including a bimetallic thermostat comprising: a bimetallic strip attached to said container at a first end and having a first electrical contact at a second end, an elongated metal strip attached at a first end to said container and having a second electrical contact at a second end, said bimetallic strip and said metal strip being parallel to each other with said second ends and first and second contacts adjacent to one another, said first ends of said bimetallic strip and metal strip being spaced away from each other a distance greater than said second ends, whereby said first contact is moved into contact with said second contact at a predetermined temperature by said bimetallic strip, and adjustable cam means for changing the position of said second contact, whereby the temperature at which said thermostat is actuated may be adjusted.

21. An article of manufacture in accordance with claim 20 in which said bimetallic thermostat further includes a supporting means having a longitudinal slot orthogonal to said metal strip, said metal strip having a flat portion, said flat portion having first and second parallel outer edges conforming to and being supported by the sides of said slot, the base of said slot being formed to support the bottom of said flat portion, said flat portion further including a first inner closed edge defining an elliptical aperture having a longitudinal axis parallel to the longitudinal axis of said slot, said supporting portion having a second inner closed edge defining a second aperture, said second closed edge having a portion extending at an angle to the longitudinal axis of said first aperture, and a fastening means having a first portion extending through said first aperture into said slot in a second portion engaging the top surface of said flat support and confining said flat support selectively with one of a plurality of different frictionalforces to firmly mount said metallic strip with one of said frictional forces and to loosely confine said metallic strip during calibration of said thermostat in such a manner that said one of said metallic strips may be moved within said supporting slot by pressure against said first edge of said second aperture.

22. As an article of manufacture, a fire alarm in accordance with claim 20 in which said cam means includes a cylindrical disk mounted to rotate with said cam means, a plurality of indicia upon said rotatable disk, said indicia indicating different temperatures, and an eccentrically mounted stem portion rotatable and eccentn'cally mounted to said compartment at one end and rigidly mounted to said disk at its other end, said stern portion having a surface between said one end and said other end, which surface is positioned to be in intimate contact with a portion of said metallic strip.

No references cited.

JOHN W. CALDWELL, Primary Examiner.

D. L. TRAFTON, Assistant Examiner. 

1. A FIRE ALARM COMPRISING A CONTAINER INCLUDING AN ALARM COMPARTMENT, A BATTERY COMPARTMENT AND A THERMOSTAT COMPARTMENT, SAID ALARM COMPARTMENT AND BATTERY COMPARTMENT BEING SEPARATE FROM SAID THERMOSTAT COMPARTMENT, AN ANNUNCIATOR OPERATIVELY MOUNTED WITHIN THE ALARM COMPARTMENT, SAID BATTERY COMPARTMENT ADAPTED TO DETACHABLY MOUNT CONVENTIONAL BATTERIES IN SERIES, A BIMETALLIC THERMOSTAT OPERATIVE BETWEEN A PREDETERMINED TEMPERATURE RANGE, SAID BIMETALLIC THERMOSTAT INCLUDING A BIMETALLIC STRIP HAVING A CONTACT AT ONE END BEING OPERATIVELY AFFIXED TO THE CONTAINER WITHIN THE THERMOSTAT COMPARTMENT AT THE OTHER END, SAID BIMETALLIC THERMOSTAT FURTHER INCLUDING A METALLIC STRIP HAVING A CONTACT AT ONE END AND BEING AFFIXED TO THE CONTAINER WITHIN THE THERMOSTAT COMPARTMENT AT THE OTHER END, THE CONTIGUOUS OTHER ENDS OF SAID STRIPS INCLUDING TERMINAL CONNECTIONS, THE CONTACT OF THE BIMETALLIC STRIP BEING ALIGNED WITH THE CONTACT OF SAID METAL STRIP, AND ANNUNCIATOR, SAID BATTERIES, AND SAID BIMETALLIC THERMOSTAT BEING OPERATIVELY CONNECTED IN A SERIES CIRCUIT, SAID SERIES CIRCUIT BEING NORMALLY OPEN AND BEING OPERATIVELY CLOSED AT A PREDETERMINED TEMPERATURE WITHIN THE PREDETERMINED TEMPERATURE RANGE, A COVER FOR THE CONTAINER INCLUDING PARTITIONS FOR SEALING OFF THE ALARM AND BATTERY COMPARTMENTS FROM EACH OTHER AND THE THERMOSTAT COMPARTMENT SAID COVER BEING PROVIDED WITH AN OPENING OVERLYING THE ALARM DEVICE FOR DISSEMINATING THE SOUND OF THE ANNUNCIATOR UPON ACTUATION, MEANS FOR THE CIRCULATION OF AIR THROUGH THE THERMOSTAT COMPARTMENT AND ABOUT THE THERMOSTAT, SAID MEANS FOR CIRCULATION OF AIR COMPRISING AIR PASSAGES FORMED ON THE COVER CONTIGUOUS TO AND OVERLYING THE THERMOSTAT COMPARTMENT WITH THE COVER BEING OPERATIVELY MOUNTED ON THE CONTAINER, SAID MEANS FOR THE CIRCULATION OF AIR COMPRISING ADDITIONAL AIR PASSAGES FORMED IN THE CONTAINER CONTIGUOUS TO THE THERMOSTAT COMPARTMENT AND ALONG AT LEAST ONE SIDE OF THE THERMOSTAT COMPARTMENT, AND SAID MEANS FOR CIRCULATION OF AIR PERMITTING AIR TO CIRCULATE THROUGH THE THERMOSTAT COMPARTMENT IN THE MOUNTED POSITION OF THE FIRE ALARM WITHIN AN ENCLOSURE BEING PROTECTED, WHEREBY AIR FOR ACTUATING THE BIMETALLIC THERMOSTAT MAY CIRCULATE THROUGH THE THERMOSTAT COMPARTMENT IN EITHER THE VERTICAL POSITION OR HORIZONTAL POSITION OF THE FIRE ALARM UPON BEING AFFIXED TO A VERTICAL OR HORIZONTAL WALL SURFACE. 